I don't think Nice would be high on my wish-list, either, particularly with children. It's a city, pebble beaches, manic traffic, nice old centre, but charmless elsewhere, and as previously said, expensive. Looking at the website, I think we actually stayed at Les Pinedes about 25 years ago (if it every did Canvas Holiday tents), when my eldest son was about seven and the youngest just a baby! The site was nice, the route down to Nice lovely, and the inland gorges and scenery were wonderful, but Nice itself was a disappointment. We stayed less than our allotted days, and moved to a campsite at Cavalaire, which was much nearer to a more suitable and child-friendly beach.
The area around Frejus/St Raphael is probably a more child-friendly place, with lots of campsites near the beaches, much better sandy beaches, and plenty of attractions to keep children happy - and where we've been back to many times when my sons were small.